// 隐式调用
function foo(el){
    console.log(el,this.id);
}
var obj={
    id:'awesome'
}
// 调用foo(..)时把this绑定到obj
//[1,2,3].forEach(foo.obj);
function func(){
    var a=2;
    bar();
    console.log(this.b);
}
foo.b=2;
function bar(){
    //console.log(a)
}
func();
function fun(count){
    this.count=count
}
var f1=new fun(2);
console.log(f1.count);//2


